Fill sheets and related fill pack assemblies

ABSTRACT

A fill sheet for cooling heat transfer fluid in a cooling tower includes an air intake end, an air outlet end, a top edge and a bottom edge. The air outlet end is positioned opposite the air intake end along a lateral axis. The top edge connects the air intake end and the air outlet end and the bottom edge also connects the air intake end and the air outlet end. The bottom edge is positioned opposite the top edge along a vertical axis. A plurality of flutes extends generally parallel to the lateral axis between the air intake end and the air outlet end. An offset extends generally parallel to the vertical axis. A first flute of the plurality of flutes transitions from a first peak at a first side of the offset to a first valley at a second side of the offset.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Patent Application No. 62/951,365, filed on Dec. 20, 2019 and titled “Fill Sheets and Related Fill Pack Assemblies,” the entire contents of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

A variety of film fills and fill sheets are available for cross-flow cooling towers that may be assembled together into fill packs. In order to distinguish and create advantages in the marketplace, it is important for a fill manufacturer to offer a product with improvements over competing fill options. Some examples of these advantages include improved tower performance through a higher efficiency fill, ease of installation, product longevity, product cost, and reduction of drift exiting the fill.

The performance of a cooling tower can be characterized by the quantity of water or other cooling fluid that can be cooled to a specified operating temperature for a certain set of ambient conditions. In order to achieve this cooling, water is sprayed onto the cooling tower fill and is exposed to an air flow, thereby causing evaporation of a small portion of water into the air, which cools the remaining water. By increasing the amount of evaporation occurring within the cooling tower, the overall performance of the tower may also be increased or improved. Since most of this evaporation occurs within the fill, changes to the fill design can significantly impact the amount of cooling a tower can achieve during operation. Specifically, changes to a cooling tower fill that reduce the pressure drop across a fill for a given air flow or otherwise improve the thermal performance of the fill, will result in a better performing cooling tower. By reducing the pressure drop across a fill, the resistance to airflow through the tower is decreased, allowing more air to pass over the water film for the same fan power, thereby causing the amount of evaporation to increase. To improve the thermal performance of a fill, increased mixing of the air and water can increase the amount of evaporation of water into the air by improving the conditions at the air-water interface. Generating mixing of the air, however, typically requires changes to the fill which also increases the pressure drop across the fill, indicating the need for fill designs which can either reduce pressure drop over existing designs with minimal impact to mixing or improved strategies for mixing which require equal or less pressure drop.

For cross-flow cooling towers, film fills are installed in the tower as a hanging fill, or as a bottom supported fill. For hanging fills, holes are punched near the top of the fill sheets to accept rails or for mounting on rails where the fill sheets are spaced along the length of the rails. This causes the individual fill sheets to be under tensile loading under the holes, but under compressive loading at the rail-sheet interface. For bottom supported fills, sheets are secured together into rigid blocks of fill, then placed on top of a support structure in the tower. Typically, bottom supported fills are easier to install into towers than hanging fills but the bottom supported fill sheets require additional structural features to resist the compressive loading seen during use, particularly during operation under loading from the water or other cooling fluid utilized in the tower or from the accumulation of external deposits, such as ice, biological foulants, scale or related other accumulated deposits that all apply additional weight and forces onto the fill. These structural features of the fill sheets, such as structural ribs or glue boss features, usually provide little to no thermal benefit for the fill and increase the pressure drop, thereby resulting in reduced tower performance. Alternative to the structural ribs and glue bosses, thicker gauge sheets may be used for the fill construction, however the increase in gauge thickness increases the total cost of the fill by adding more material to each fill sheet.

For film fills used in cross-flow towers, all fills contain a dedicated heat transfer area, while some also contain an integral drift eliminator near the air outlet of the fill and/or a louver section near the air inlet of the fill. The heat transfer area of the fill is responsible for the thermal performance of the fill by providing a large surface area for water to spread out on the surfaces of the fill to increase contact with the air, mixing the air as it flows through the fill and mixing the water film as it flows over the sheets, while maintaining a low pressure drop across the fill. Typically, the heat transfer surface for cross-flow fills consists of fluted fill sheets with small surface features (microstructure) patterned across the surface or fill sheets with more aggressive patterned features and less pronounced flute features. For fills with flutes, the flutes are usually continuous across the heat transfer area or have a generally constant cross-section along their length and are commonly cross corrugated, although may be oriented horizontally or vertically.

Although most of the bulk water adheres to the surface of a film fill, some of the water forms small droplets and escapes the fill through the air outlet, otherwise known as drift. Drift is undesirable, as the drift represents a loss of water or other cooling fluid from the system and the loss of water or other cooling fluid has a cost to replenish, both itself and any treatment chemicals contained within the cooling fluid. The drift may also have a deleterious impact on surrounding equipment and environments since the drift may contain chemicals, salts and bacteria present in the circulating water or fluid. For cross-flow tower film fills, drift elimination features are sometimes included on the air outlet side of the sheet to capture these drift droplets and prevent them from escaping the cooling tower, which are referred to as drift eliminators and may be comprised of integral drift eliminators (“IDs”). For cross-flow film fills, there are typically two different types of drift eliminators which may be integrated, including the tube drift eliminator and the blade drift eliminator. Generally, tube drift eliminators are angled tubes formed into the ID section of the fill by aligning drift corrugations of adjacent sheets. As water droplets enter the tubes entrained in the air stream, the momentum of the droplets causes them to impact the tube wall as the airflow changes direction while following the angled tube of the ID. A vertical channel is typically included at the inlet of the integral drift eliminator tubes to allow water collected on the surface of the integral drift eliminator to drain out of the fill into a lower catch basin, and to provide vertical structural support for bottom supported fills. One limitation of current implementations of this type of drift eliminator is introduced when water reaches the tube inlet of the eliminator. When water reaches the transition between the tube section and the drain, some water may be pushed along part of the top wall of the tube by the air before falling off into the air stream. By introducing droplets farther into the eliminator, it becomes easier for these droplets to escape out of the eliminator without impacting a wall, thereby reducing eliminator performance. Integral blade drift eliminator designs accomplish drift removal by creating a large vertically oriented ridge, near the air outlet of the fill to change the direction of airflow. The momentum of the water droplets at the integral drift eliminator inlet causes an impact with the ridge walls, eliminating the drift from the airstream. Other structural features such as ribs or spacers may be included before or after the eliminator ridge to ensure the sheets remain separated during operation and to stiffen the fill and/or sheet, as well as the assembled fill pack.

At the air inlet of the fill, integral louvers are sometimes included into the fill design to prevent water from splashing out of the front of the fill. These integral louvers are usually comprised of corrugations which are angled downward as they protrude into the fill, to provide a sloped surface for the water to run down, thereby preventing water or other cooling fluid from reaching the front of the fill. The corrugations on each sheet may be assembled together to form tubes or remain parallel to adjacent sheet corrugations with additional sheet spacer features added to the design.

BRIEF SUMMARY OF THE INVENTION

Briefly stated, the preferred invention is directed to a fill sheet for cooling a heat transfer fluid in a cooling tower when assembled into fill packs comprised of pluralities of fill sheets for use in a cross-flow cooling tower. The fill sheet includes an air intake end, an air outlet end positioned opposite the air intake end along a lateral axis, a top edge connecting the air intake end and the air outlet end and a bottom edge connecting the air intake end and the air outlet end. The bottom edge is positioned opposite the top edge along a vertical axis. The heat transfer fluid is configured for flowing between the top edge and the bottom edge. A plurality of flutes extends generally along the lateral axis between the air intake end and the air outlet end. An offset or transition feature provides a flat section of macrostructure and extends generally parallel to the vertical axis. A first flute of the plurality of flutes transitions from a first peak at a first side of the offset to a first valley at a second side of the offset. The offset or transition feature includes a rib extending generally parallel to the vertical axis and a spacer to provide structural support for the offset. Microstructure is preferably integrally formed into the offset and has a generally herringbone shape. The spacer is preferably comprised of a first plurality of spacers, wherein each of the plurality of flutes includes one of the first plurality of spacers positioned thereon at the offset or transition feature. The rib is preferably comprised of an intermediate rib, including a first intermediate rib and a second intermediate rib and the spacer is comprised of an intermediate column of spacers.

In another aspect, the preferred invention is directed to a fill sheet for cooling heat transfer fluid in a cooling tower when arranged into fill packs comprised of pluralities of fill sheets. The fill sheet includes an air intake end, an air outlet end positioned opposite the air intake end along a lateral axis, a top edge connecting the air intake end and the air outlet end and a bottom edge connecting the air intake end and the air outlet end. The bottom edge is positioned opposite the top edge along a vertical axis. A plurality of spacers extends from a heat transfer area of the fill sheet between the air intake end, the air outlet end, the top edge and the bottom edge. The plurality of spacers includes a first spacer having a first head end and a first tail end. The first head end is positioned closer to the top edge than the first tail end. The first spacer defines a first spacer axis. The first spacer axis defines a first acute spacer angle with the lateral axis. The plurality of spacers includes a second spacer having a second head end and a second tail end. The second head end is positioned closer to the top edge than the first tail end. The second spacer defines a second spacer axis. The second spacer axis defines a second acute spacer angle with the lateral axis. The first spacer axis extends at an opposite side of the vertical axis relative to the second spacer axis.

In yet another aspect, the preferred invention is directed to a fill pack for cooling heat transfer fluid in a cooling tower. The fill pack includes a first fill sheet having a first top edge, a first bottom edge and a first heat transfer area between the first top edge and the first bottom edge and a second fill sheet having a second top edge, a second bottom edge and a second heat transfer area between the second top edge and the second bottom edge. A first plurality of spacers extends generally perpendicularly relative to a first sheet plane from the first fill sheet. The first plurality of spacers includes a first spacer having a first head end and a first tail end. The first head end is positioned closer to the first top edge than the first tail end. A second plurality of spacers extends generally perpendicularly relative to a second sheet plane from the second fill sheet. The second plurality of spacers includes a second spacer having a second head end and a second tail end. The second head end is positioned closer to the second top edge than the second tail end. The first head end is positioned proximate the second head end in an installed configuration. A vertical axis is defined generally perpendicularly relative to the first and second top edges and the first and second bottom edges. The first tail end extends toward an opposite side of the vertical axis relative to the second tail end.

In a further aspect, the preferred invention is directed to a fill pack for cooling heat transfer fluid in a cooling tower. The fill pack includes a first fill sheet having a first air intake side, a first top edge, a first air outlet side and a first heat transfer area between the first air intake side and the first air outlet side and a second fill sheet having a second air intake side, a second top edge, a second air outlet side and a second heat transfer area between the second air intake side and the second air outlet side. An integral drift eliminator is associated with the first and second air outlet sides in an installed configuration. The drift eliminator defines a plurality of tubes with a drift eliminator inlet positioned proximate the first and second heat transfer areas and a drift eliminator outlet spaced away from the first and second heat transfer areas. The plurality of tubes extends generally toward the first and second top edges from the drift eliminator inlet toward the drift eliminator outlet. Each of the plurality of tubes includes a blocking structure at the drift eliminator inlet configured to block heat transfer fluid at the drift eliminator inlet to promote droplet formation and capture of the heat transfer fluid in the drift eliminator.

In an additional aspect, the preferred invention is directed to a fill sheet for cooling heat transfer fluid in a cooling tower when assembled into fill packs comprised of pluralities of fill sheets. The fill sheet includes an air intake end, an air outlet end positioned opposite the air intake end along a lateral axis, a top edge connecting the air intake end and the air outlet end and a bottom edge connecting the air intake end and the air outlet end. The bottom edge is positioned opposite the top edge along a vertical axis. A microstructure is formed on the fill sheet. A support rib extends between the top edge and the bottom edge. The support rib includes a first support rib and a second support rib. The first and second support ribs are spaced laterally from each other along the lateral axis and extend substantially parallel to the vertical axis. The support rib has a first support rib portion having a first support rib length. The first support rib includes a first rib height and the second support rib including a second rib height. The microstructure has a microstructure height. The first rib height is less than the microstructure height in the first support rib portion and the second rib height is greater than the microstructure height in the first support rib portion. The support rib is preferably comprised of an outlet side rib positioned proximate the air outlet end. The first support rib portion preferably has a first support rib portion length. In the preferred embodiment, the first rib height may be comprised of a rib minimum height and the second rib height may be comprised of a rib maximum height with the rib height transitions between the rib maximum heights and the rib minimum heights.

In a further aspect, the preferred present invention is directed to a fill sheet for cooling heat transfer fluid in a cooling tower when assembled into fill packs comprised of pluralities of fill sheets. The fill sheet includes an air intake end, an air outlet end positioned opposite the air intake end along a lateral axis, a top edge connecting the air intake end and the air outlet end and a bottom edge connecting the air intake end and the air outlet end. The bottom edge is positioned opposite the top edge along a vertical axis. A plurality of ribs positioned generally between the air intake end and the air outlet end. An intermediate rib is positioned generally between the air intake end and the air outlet end. The intermediate rib includes a first intermediate rib and a second intermediate rib. The first intermediate rib extends from a top end proximate the top edge to first end. The second intermediate rib extends from a bottom end proximate the bottom edge to a second end. The second rib includes the second end and a third end. The first end is positioned proximate the second end. An offset extends generally parallel to the vertical axis. A first flute of a plurality of flutes transitions from a first peak at a first side of the offset to a first valley at a second side of the offset. The intermediate rib is positioned at the offset. The first end of the first rib is positioned proximate the second end of the second rib. At least one of the first and second ribs are intersected by the lateral axis between the top end and the third end. The first and second ribs are preferably spaced at a lateral spacing that is between one-quarter and two inches (¼-2″). The first and second ribs of the preferred embodiments may be comprised of any one of intake side ribs, outlet side ribs or intermediate ribs. The first rib may be comprised of a first intermediate rib segment and the second rib may be comprised of a second intermediate rib segment, therein a first end and a second end are positioned proximate a middle of the fill sheet in the preferred embodiment.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

FIG. 1 is a front elevational view of a fill sheet in accordance with a first preferred embodiment of the present invention;

FIG. 1A is a magnified front perspective view of a portion of the fill sheet of FIG. 1, taken from within shape 1A of FIG. 1;

FIG. 1B is a side perspective view of the fill sheet of FIG. 1, taken along the line 1B-1B of FIG. 1;

FIG. 1C is a wireframe front perspective view of a portion of the fill sheet of FIG. 1, representing undulating flutes and offsets of the fill sheet;

FIG. 2 is a bottom perspective view of a portion of an air outlet section of the fill sheet of FIG. 1, taken generally rearwardly of the line 2-2 of FIG. 1;

FIG. 2A is a front elevational view of the portion of the air outlet section of the fill sheet of FIG. 2;

FIG. 2B is a cross-sectional view of a portion of the fill sheet of FIG. 1, taken along line 2B-2B of FIG. 2;

FIG. 2C is a cross-sectional view of a portion of the fill sheet of FIG. 1, taken along line 2C-2C of FIG. 2A;

FIG. 2D is a cross-sectional line view of the fill sheet of FIG. 1, taken along line 2D-2D of FIG. 2;

FIG. 3 is a bottom plan view of a pair of fill sheets of FIG. 1 installed or assembled together to define a fill pack;

FIG. 3A is a cross-sectional line view of the fill pack of FIG. 3, taken along line 3A-3A of FIG. 3;

FIG. 3B is a cross-sectional line view of the fill pack of FIG. 3, taken along line 3B-3B of FIG. 3;

FIG. 3C is a cross-sectional line view of the fill pack of FIG. 3, taken along line 3C-3C of FIG. 3;

FIG. 4 is a magnified bottom plan view of a portion of the fill pack of FIG. 3, wherein spacers of the fill sheet are shown in an installed or assembled configuration;

FIG. 5 is a front elevational representation of the shapes of the spacers of FIG. 4;

FIG. 6 is a front elevational representation of alternative shapes for the spacers of FIG. 4;

FIG. 7 is a front elevational view of a fill sheet in accordance with a second preferred embodiment of the present invention, which includes an integrated drift eliminator at an air outlet side of the fill sheet;

FIG. 8 is a front perspective view of the fill sheet of FIG. 7, taken from within shape 8-8 of FIG. 7;

FIG. 9 is a cross-sectional view of a portion of a pair of fill sheets installed or assembled together to define a fill pack, taken along line 9-9 of FIG. 7 and generally showing a flute of a drift eliminator and connection of the drift eliminator flute to a cooling section of the fill sheets; and

FIG. 10 is a front elevational representation of a fill sheet in accordance with a third preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain terminology is used in the following description for convenience only and is not limiting. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one element but instead should be read as meaning “at least one”. The words “right,” “left,” “lower,” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” or “distally” “front” or “rear” and “outwardly” or “proximally” refer to directions toward and away from, respectively, the geometric center or orientation of the fill sheets or fill packs and related parts thereof. The terminology includes the above-listed words, derivatives thereof and words of similar import.

It should also be understood that the terms “about,” “approximately,” “generally,” “substantially” and like terms, used herein when referring to a dimension or characteristic of a component of the invention, indicate that the described dimension/characteristic is not a strict boundary or parameter and does not exclude minor variations therefrom that are functionally the same or similar, as would be understood by one having ordinary skill in the art. At a minimum, such references that include a numerical parameter would include variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit.

Referring to FIGS. 1-3C, a fill sheet, generally designated 10, in accordance with a first preferred embodiment of the present invention has a heat transfer section 11, along with an air inlet portion 12, which may include an integral louver (not shown), an air outlet portion 14, which may include an integral drift (See FIGS. 7-9), and/or other standard end features at the inlet portion 12 and/or the outlet portion 14, as well as additional features, such as intermediate honeycombs. The fill sheet 10 is not limited to including the integral louver or the integral drift, neither of which are shown in the first preferred embodiment of the fill sheet 10, and may function without the louver and drift or may include alternative features attached to, integrally formed with, positioned adjacent to or abutting the air inlet and outlet portions 12, 14, such as non-integral louvers and drift that abut, but are not integrally formed with the fill sheet 10. The air inlet portion 12 of the first preferred fill sheet 10, which may include an integral louver, is positioned at the air intake side 10 a of the sheet 10 and the air outlet portion 14, which may include an integral drift, is positioned at the air outlet side 10 b of the preferred cross-flow fill sheet 10.

The heat transfer section 11 of the first preferred fill sheet 10 includes a herringbone-shaped microstructure 11 a or the microstructure 11 a has a generally herringbone shape to increase the surface area of the fill sheet 10 in the heat transfer section 11 and provide mixing of the air and water during operation. The microstructure 11 a is not limited to being comprised of the herringbone-shaped microstructure and may be comprised of alternatively sized and shaped microstructure that increases the surface area of the fill sheet 10 in the heat transfer section 11 to expose additional water film area to the airflow. The microstructure 11 a preferably has a smaller microstructure height H_(s) when compared to the height of the macrostructure of the preferred fill sheet 10, wherein the macrostructure includes features such as the plurality of flutes 18, as is described in greater detail below. In the preferred embodiments, the microstructure height H_(s) is three hundredths of an inch to one-half inch (0.03-0.5″) but is not so limited and may fall outside this range depending on designer preferences, microstructure type, cooling tower type, expected loading and related design considerations and preferences. The microstructure height Hs, however, of the preferred microstructure 11 a is within the preferred range of the microstructure height H_(s) and is adaptable for use with the preferred fill sheets 10.

The heat transfer section 11 of the fill sheet 10 also includes a spacer 16, which may be comprised of pluralities of spacers 16. The spacers 16 may be comprised of glue bosses, peg spacers or other similar structures or features that space the fill sheets 10, 9 a, 9 b from each other in the assembled or installed configurations. The spacers 16 preferably extend from opposing front and rear surfaces of the fill sheet 10 and mate with opposing spacers 16 on adjacent fill sheets 10, but are not so limited and may be configured to extend from only a single surface of the fill sheet 10 or may be otherwise sized and configured to space the fill sheets 10 in the assembled configurations. The spacers 16 on the adjacent fill sheets 10 in an assembled configuration are also preferably comprised of mating glue bosses or peg spacers that facilitate spacing of the assembled fill sheets 10 relative to each other. The spacers 16 are not limited to mating glue bosses or peg spacers and may be comprised of nearly any feature of the fill sheets 10 that facilitates spacing of the adjacent fill sheets 10 relative to each other in the assembled configuration, including suspension or hanging of the fill sheets 10 next to each other at predetermined spacing intervals or distances during operation. The spacers 16 may assist in joining or bonding the adjacent fill sheets 10 together in the assembled configuration or may provide general spacing between the adjacent fill sheets 10 in the assembled configuration. The configuration and operation of the spacers 16 are described in greater detail below. The fill sheets 10 of the preferred embodiments may also include spacers 16 with alignment or connection features 19 extending therefrom. The spacers 16 preferably provide a surface for mating with a spacer 16 from an adjacent fill sheet 10 to appropriately space a first fill sheet 9 a from a second fill sheet 9 b in the assembled or installed configuration. The alignment or connection features 19 preferably facilitate proper alignment of the first sheet 9 a relative to the second sheet 9 b and/or provide for engagement or connection of the adjacent fill sheets 10 in the assembled or installed configuration.

The heat transfer section 11 of the fill sheet 10 further includes flutes 18 arranged thereon that generally extend parallel or substantially parallel to a lateral axis 20 of the fill sheet 10. The lateral axis 20 extends generally horizontally in an installed configuration of the fill sheets 10 and is oriented generally perpendicular to a vertical axis 22. The flutes 18 preferably guide the airflow through the heat transfer area 11, generally along the lateral axis 20 from the intake side 10 a to the outlet side 10 b.

The first preferred fill sheet 10 also includes an improved rib configuration for vertical and lateral rigidity and strength of the fill packs in the assembled configuration, including intake side ribs 24 and outlet side ribs 26 that extend generally parallel to the air intake side 10 a and air outlet side 10 b, respectively. The intake side ribs 24 and the outlet side ribs 26 are preferably integrally formed in the fill sheet 10 proximate the air intake side 10 a and the air outlet side 10 b, respectively and adjacent to the heat transfer area 11 or within the heat transfer area 11. The intake side ribs 24 and the outlet side ribs 26 are described in greater detail below.

Referring to FIGS. 7-9, in a second preferred embodiment, a fill sheet 10′ has similar features to the first preferred fill sheet 10 and the same reference numerals are utilized to identify similar or the same features, with a prime symbol (′) utilized to distinguish the features of the second preferred embodiment from the first preferred embodiment. The second preferred fill sheet 10′ includes an integral drift eliminator 50 that improves upon known tube based integral drift eliminators (not shown) by introducing a blocking structure 100 to improve drift performance, as is described greater detail below.

Referring to FIGS. 1 and 7, in the first and second preferred embodiments, the fill sheets 10, 10′ are oriented in the cooling tower and configured at a forward lean or to have a pack angle Δ, A′ of approximately five to ten (5-10) degrees in order to offset the effects of the crossing airflow on the vertically flowing water on the fill sheet surfaces during operation. As the water flows down the sheets 10, 10′, generally parallel to the vertical axis 22, 22′, the air tends to push the water toward the air outlet side 10 b, 10 b′ of the fill sheets 10, 10′ due to friction at the air-water interface. The fill sheets 10, 10′, thereby lean into the direction of air flow, generally along the lateral axis 20, 20′ such that a top front corner of the fill sheets 10, 10′ near the intersection of the air intake side 10 a, 10 a′ and a top edge 28, 28′ is positioned closest to the air inlet of the tower. The lower front corner of the fill sheets 10, 10′ near the intersection of the air intake side 10 a, 10 a′ and a bottom edge 30, 30′ is the portion of the air intake side that is positioned furthest from the air inlet of the tower.

Referring to FIGS. 1-3C, the heat transfer area 11 of the fill sheet 10 is comprised of the herringbone-shaped microstructure 11 a formed over the flutes 18 and covers a majority of the interior of the fill sheet 10. The geometry of the flutes 18 is generally comprised of individual flutes 18 oriented substantially in the air travel direction or generally parallel to the lateral axis 20. The fill sheets 10 also preferably include transition features 32, which may be comprised of offsets 32 in the flutes 18. The transition features 32 preferably provide a generally flat macrostructure extending generally parallel to the vertical axis 22 or pitched by the pack angle Δ, Δ′ from the vertical axis 22. A first flute 18 of the plurality of flutes 18 transitions from the flat section of the transition feature 32 to the arcuate macrostructure spaced from the transition feature 32 (See FIG. 1C). The flat section preferably includes a rib or support 38 extending generally parallel to the vertical axis 22 and a spacer 16 to provide lateral support for the rib or support 38. The spacer 16 is preferably positioned proximate the rib or support 38 to provide lateral support for the rib or support 38 and is not limited to being positioned in the flat section or transition feature 32 but is preferably positioned proximate the rib or support 38 to provide lateral support. The spacer 16 is preferably comprised of a first plurality of spacers 16 along or at the offset 32, wherein each of the plurality of flutes 18 is associated with or includes one of the first plurality of spacers 16 positioned thereon at the offset, flat section or transition feature 32. The pluralities of spacers 16 of the first preferred fill sheet 10 are positioned at each of the offsets 32 proximate the air intake side 10 a, proximate the air outlet side 10 b, and proximate the intermediate vertical ribs 38, respectively.

The preferred fill sheets 10 include several intermediate offsets 32 in the flutes 18 where the peaks 36 of the flutes 18 transition to valleys 34, and vice versa, generally along the air flow direction or the lateral axis 20. The offsets or transition features 32 are typically positioned proximate to the columns of spacers 16 such that two adjacent fill sheets 10, such as the first and second fill sheets 9 a, 9 b (FIGS. 3-3C) may be connected together or positioned next to each other to define a fill pack 8. The first preferred fill sheets 10 and the fill pack 8 of FIGS. 1C and 3-3C show the transition of the peaks 36 to the valleys 34 and the valleys 34 to the peaks 36 on opposite sides of the offsets or transition features 32 in the direction of the lateral axis 20, thereby creating a generally parallel orientation of the adjacent first and second fill sheets 9 a, 9 b in the heat transfer area 11. The position of the offsets 32 in the air travel direction or generally parallel to the lateral axis 20 is staggered between the adjacent first and second fill sheets 9 a, 9 b for any given vertical position on the fill pack 8. By staggering the offsets 32, a majority of the profiles of the flutes 18 for the fill pack 8 is parallel (FIGS. 3C and 3D) to the adjacent first and second sheets 9 a, 9 b, while short segments of the fill pack 8 between sets of offsets 32 have an opposing profile or adjacent peaks 36 to valleys 34 in the offsets 32 of the adjacent sheets 9 a, 9 b (FIG. 3B), thereby providing a location for spacers 16 to be incorporated into the design without significantly protruding into the airstream of the flutes 18 and contributing to pressure drop. This first preferred configuration of the flutes 18 provides an advantage over prior tube-based flute arrangements by allowing the majority of the profiles of the flutes 18 of the fill pack 8 to remain generally parallel to and between the adjacent sheets 9 a, 9 b, thereby reducing areas of restricted air flow between the peaks 36 and valleys 34 of adjacent sheets 9 a, 9 b of the fill pack 8. The staggered offsets 32 also create a short tube region within the fill pack 8, which offers structural advantages over a flute design that only consists of parallel flute profiles. By providing short segments proximate the offsets 32 where the flutes 18 are aligned into a tube configuration with the peaks 36 and valleys 34 of the adjacent sheets 9 a, 9 b generally aligning in the offsets 32, the lateral stiffness of the fill pack 8 is increased, without the need for large spacer features intruding into the airflow region. In addition, the transition regions on either side of the tube structure of the offsets 32 provide a generally flat section to add vertical ribs or supports, such as intermediate vertical ribs or supports 38 without cutting through the profile of the flutes 18. The intermediate vertical ribs or supports 38 strengthen the fill pack 8 without significantly increasing the pressure drop across the fill pack 8 between the air intake side 10 a and the air outlet side 10 b.

Referring to FIGS. 3 and 4-6, in addition to the improved geometry of the flutes 18 in the fill pack 8 of the first preferred embodiments used in the cross-flow fill design, improvements have been made to the spacers 16 used to space the adjacent fill sheets 9 a, 9 b apart to define the fill packs 8. The first preferred embodiment of the spacers 16 has a generally angled teardrop or raindrop shaped spacer 16, at least in the heat transfer area 11 where the microstructure 11 a is formed on the fill sheets 10. In an installed configuration, a first spacer 16 a of the first fill sheet 9 a mates with and is joined, positioned in facing engagement or positioned proximate to a second spacer 16 b on the second, adjacent fill sheet 9 b to space the first and second fill sheets 9 a, 9 b at a predetermined distance from each other and may facilitate joining or connection of the adjacent fill sheets 9 a, 9 b. The preferred fill sheets 9 a, 9 b have a plurality of spacers 16 that extend from both opposing faces of the fill sheets 9 a, 9 b to mate with adjacent fill sheets 9 a, 9 b, 10 in the installed configuration. As a non-limiting example, the first preferred fill sheets 9 a, 9 b, 10 have three columns of fourteen (14) spacers 16 proximate a middle of the fill sheets 9 a, 9 b, 10 along the offsets 32 and the air intake and air outlet sides 10 a, 10 b, respectively. The fill sheets 9 a, 9 b also include pluralities of spacers 16 positioned adjacent the air intake and air outlet sides 10 a, 10 b with the alignment or connection features 19 thereon. The three columns of spacers 16 include an intermediate column of spacers 15 b, an air intake side column of spacers 15 a and an air exit side column of spacers 15 c. In the first preferred embodiment, the air intake side column of spacers 15 a is positioned at an air intake side offset 32, the intermediate column of spacers 15 b is positioned at an intermediate offset 32 and the air exit side column of spacers 15 c is positioned at an air exit side offset 32. The intermediate column of spacers 15 b is positioned between a first intermediate rib 38 a and a second intermediate rib 38 b at the intermediate offset 32. The first intermediate rib 38 a is positioned between the intermediate column of spacers 15 b and the air intake side 10 a and the second intermediate rib 38 b is positioned between the intermediate column of spacers 15 b and the air exit side 10 b. The fill sheets 9 a, 9 b, 10 are not limited to including the fourteen (14) spacers 16 in each of the columns of spacers 15 a, 15 b, 15 c or to the specific locations shown in the preferred embodiments and may include more or less spacers 16, depending on the size of the fill sheets 9 a, 9 b, 10, the expected loading on the fill sheets 9 a, 9 b, 10, the expected environment, designer preferences and related factors. The fill sheets 9 a, 9 b, 10 may include nearly any number of spacers 16 that facilitate spacing or joining of the adjacent sheets 9 a, 9 b, 10 together in the installed configuration, are able to withstand the normal operating conditions of the spacers 16 and perform the functions of the spacers 16, as described herein.

In the first preferred embodiment, each of the spacers 16 includes a generally wider and relatively semi-circular shaped head end 40 and a narrower tail end 42. The first spacer 16 a includes a first head end 40 a and a first tail end 42 a and the second spacer 16 b includes a second head end 40 b and a second tail end 42 b. The head ends 40 and the tail ends 42 define the teardrop or raindrop shape of the spacer 16, wherein the tail ends 42, 42 a, 42 b are generally rounded, particularly in comparison to a traditional teardrop or raindrop shape. In the installed configuration, the head ends 40 of adjacent spacers 16 generally mate and provide surfaces for joining the spacers 16 and the tail ends 42 extend away from each other in the installed configuration, generally to opposite sides of the vertical axis 22. The tail ends 42 of the first preferred embodiment extend away from the head ends 40 along a spacer axis 17. In the first preferred embodiment, the first spacer 16 a includes a first spacer axis 17 a and the second spacer 16 b includes a second spacer axis 17 b. The first and second spacer axes 17 a, 17 b preferably define first and second acute spacer angles Ωa, Ωb, respectively, with the lateral axis 20 that are approximately ten to eighty degrees (10-80°), but are not so limited and may take on nearly any acute angle that facilitates performance of the functioning of the spacers 16 and withstands the normal operating conditions of the spacers 16, such as within the range of approximately twenty to fifty degrees (20-50°) or approximately thirty-five degrees (35°). The first spacer axis 17 a preferably extends at a first side of the vertical axis 22 and the second spacer axis 17 b preferably extends at a second, opposite side of the vertical axis 22, such that the first and second spacer axes 17 a, 17 b extend at opposite sides of the vertical axis 22. This extension of the first and second spacer axes 17 a, 17 b at opposite sides of the vertical axis 22 results in the first and second tail ends 42 a, 42 b being spaced from each other in an installed configuration such that cooling fluid generally does not collect at and bridge between the first and second tail ends 42 a, 42 b, particularly if they were to substantially mate. The first spacer axis 17 a preferably extends from a central portion of the first head end 40 a through a central portion of the first tail end 42 a and the second spacer axis 17 b preferably extends from a central portion of the second head end 40 b through a central portion of the second tail end 42 b, even if the first and second spacers 16 a, 16 b have some curvature to the tail ends 42 a, 42 b and is not necessarily straight or uniformly shaped. The first and second spacer axes 17 a, 17 b also preferably define a separation angle μ measured between the first and second acute spacer angles Ωa, Ωb across the vertical axis 22. The separation angle μ is preferably between approximately twenty and one hundred sixty degrees (20-160°), preferably approximately one hundred twenty degrees (120°). The separation angle μ plus the first and second spacer angles Ωa, Ωb preferably sum to one hundred eighty degrees (180°).

In the first preferred embodiment, adjacent spacers 16, such as the first and second spacers 16 a, 16 b, are oriented with their tail ends 42 a, 42 b extending in opposite directions or to opposite sides of the vertical axis 22, thereby forming an upside down V-shape when viewed from the front or rear (FIGS. 5 and 6). This mis-alignment of the tail ends 42, 42 a, 42 b allows water, which hits the head ends 40, 40 a 40 b of the pair of spacers 16, 16 a, 16 b, to run down the sloped side surfaces of each of the spacers 16, 16 a, 16 b and separate near the tail ends 42, 42 a, 42 b of the spacers 16, 16 a, 16 b. In contrast, prior art glue bosses that fully align and have generally the same size and shape result in the water or other cooling fluid flowing over the prior art glue bosses and forming a film of water below the connection, which spans between the two associated fill sheets and impedes airflow. The inverted V shape formed by the tail ends 42, 42 a, 42 b of the adjacent spacers 16, 16 a, 16 b is the preferred shape to provide a contact surface to space adjacent fill sheets 10, 9 a, 9 b and to prevent water sheeting, while minimizing the height of the spacer profile between the adjacent fill sheets 10, 9 a, 9 b of the fill packs 8 in the waterflow direction or generally parallel to the vertical axis 22. The preferred spacers 16 have the teardrop or raindrop shape, but this shape is not limiting. For example, in an alternative preferred embodiment, the spacers 16 may have a generally rectangular shape (FIG. 6), or any shape which forms a contact feature with an adjacent spacer feature near the top of the connection, and slopes downward and away from the adjacent spacer 16 relative to the vertical axis 22. The adjacent spacers 16, 16 a, 16 b are preferably glued or otherwise secured together, such as by ultrasonic welding or mechanical joining, at the mating surfaces in the installed configuration to connect the fill sheets 10, 9 a, 9 b together, thereby forming the fill packs 8. The spacers 16, 16 a, 16 b are not limited to being glued or otherwise joined together in the installed configuration and may act exclusively as spacers to space the adjacent fill sheets 10, 9 a, 9 b relative to each other in the installed configuration, such as when the fill sheets 10, 9 a, 9 b hang from a rail adjacent to each other in the tower, but are not otherwise joined or connected at the spacers 16, 16 a, 16 b. In addition, the spacers 16, 16 a, 16 b may include connection features that secure the spacers 16, 16 a, 16 b together in the installed configuration or may be otherwise connected or joined together in the installed configuration, such as by ultrasonic welding, mechanical deformation, fastening or otherwise securing the mating spacers 16, 16 a, 16 b together in the installed configuration.

Referring to FIGS. 1-3C, structural support is provided to the first preferred fill sheets 10, 9 a, 9 b and fill packs 8 by the intake side ribs 24, the outlet side ribs 26 and the intermediate vertical ribs or supports 38, as well as the remaining body of the fill sheets 10, 9 a, 9 b. Each of the intake and outlet side ribs 24, 26 and the intermediate ribs 38 is preferably comprised of two substantially vertical support ribs 24 a, 24 b, 26 a, 26 b, 38 a, 38 b extending along the height of the fill sheet 10, 9 a, 9 b, generally parallel to the air intake side 10 a and the air outlet side 10 b. In the first preferred embodiment, the support ribs 24 a, 24 b, 26 a, 26 b, 38 a, 38 b are not fully vertical, but are oriented substantially parallel to the air intake and air outlet sides 10 a, 10 b of the fill sheets 9 a, 9 b, 10, such that the support ribs 24 a, 24 b, 26 a, 26 b, 38 a, 38 b are oriented generally at the pack angle Δ, Δ′ of approximately five to ten (5-10) degrees relative to the vertical axis 22, but are not so limited and may be otherwise oriented and configured. The microstructure 11 a of the heat transfer area 11 of each of the fill sheets 10, 9 a, 9 b is preferably comprised of angled bands of microstructure 11 a in the herringbone arrangement, extending between at least the first structural intake and outlet side ribs 24 b, 26 a, respectively, in the heat transfer area 11. The preferred support ribs 24, 26, 38, including the intake side ribs 24, 24 a, 24 b, the outlet side ribs 26, 26 a, 26 b and the intermediate ribs 38, 38 a, 38 b, extend generally vertically along the fill sheet 10, 9 a, 9 b in the installed configuration. The ribs 24 a, 24 b, 26 a, 26 b, vary in height in an alternating pattern as they extend along the fill sheet 10, 9 a, 9 b from and between the top edge 28 and the bottom edge 30. In the preferred embodiment, the intake and outlet side ribs 24 a, 24 b, 26 a, 26 b alternate between a maximum height H_(x) and a minimum height H_(n). The pairs of first and second intake side ribs 24 a, 24 b of the intake side rib 24, the first and second outlet side ribs 26 a, 26 b of the outlet side rib 26, and the first and second intermediate supports 38 a, 38 b of the intermediate support 38 are designed such that there is preferably at least one rib or support 24 a, 24 b, 26 a, 26 b, 38 a, 38 b with a height, such as the rib maximum height H_(x) extending past or being greater than the microstructure height H_(s) of the microstructure 11 a on any given position along the lengths of the individual ribs or supports 24, 26, 38 on the fill sheets 10, 9 a, 9 b.

In the first preferred embodiment, the first and second air intake ribs 24 a, 24 b are configured such that while the first air intake rib 24 a has the maximum height H_(x) that extends past or is greater than the microstructure height H_(s) of the microstructure 11 a and the second air intake rib 24 b extends below or has the rib minimum height H_(n) that is less than the microstructure height H_(s) of the microstructure 11 a. Similarly, the first and second outlet side ribs 26 a, 26 b are configured such that while the first outlet side rib 26 a has the rib maximum height H_(x) that extends past or is greater than the microstructure height H_(s) of the microstructure 11 a, the second outlet side rib 26 b has the rib minimum height H_(n) that dips below or is less than the microstructure height H_(s) of the microstructure 11 a. The first and second intermediate ribs or supports 38 a, 38 b are similarly configured in the first preferred embodiment in that the first and second intermediate ribs 38 a, 38 b are laterally spaced, but are differently configured in that the first intermediate rib 38 a substantially ends at a height where the second intermediate rib 38 b begins. There may be sections where both of the first and second inlet side ribs 24 a, 24 b, the first and second outlet side ribs 26 a, 26 b and the first and second intermediate ribs or supports 38 a, 38 b are taller than the surrounding microstructure 11 a to provide additional support at the base of the fill sheets 10, 9 a, 9 b and fill packs 8, such as where the fill pack 8 meets the supporting structure underneath the fill pack 8 in an assembled configuration in the tower. The air intake and outlet ribs 24, 26 are, however, preferably configured such that when one of the pair of first and second ribs 24 a, 24 b, 26 a, 26 b, respectively, is at its greatest height relative to the microstructure 11 a, the adjacent one of the pair of first and second ribs 24 a, 24 b, 26 a, 26 b, respectively, is at its smallest height or is generally below the height of the microstructure 11 a and is substantially embedded in the microstructure 11 a. The first and second ribs 24 a, 24 b, 26 a, 26 b, therefore, have alternating tapers between the top edge 28 and the bottom edge 30.

The intake side rib 24 and the outlet side rib 26 are not limited to extending from the top edge 28 to the bottom edge 30. The intake side rib 24 and the outlet side rib 26 may extend proximate to the top and bottom edges 28, 30 and may include some interruptions along their length, but the intake and outlet side ribs 24, 26 preferably extend to the top and bottom edges 28, 30 and are comprised of the alternately extending pairs of first and second ribs 24 a, 24 b, 26 a, 26 b that alternatively taper relative to each other. The intake and outlet side ribs 24, 26 extend to and between the top and bottom edges 28, 30 in the preferred embodiments. The intake and outlet side support ribs 24, 26 include the pairs of first and a second support ribs 24 a, 24 b, 26 a, 26 b. The first and second support ribs 24 a, 24 b, 26 a, 26 b are spaced laterally from each other along the lateral axis 20 and extend substantially parallel to the vertical axis 22 or the intake and outlet sides 10 a, 10 b. The intake and outlet side ribs 24, 26 have a first support rib portion 33 having a first support rib length or first support rib portion length L_(r1). The first support ribs 24 a, 26 a include a first rib height and the second support ribs 24 b, 26 b include a second rib height. The first rib height is less than the microstructure height in the first support rib portion 33 and the second rib height is greater than the microstructure height in the first support rib portion 33. The intake and outlet side ribs 24, 26 of the first preferred embodiment also have a second support rib portion 35 having a second support rib length or second support rib portion length L_(r2). The first rib height is greater than the microstructure height in the second support rib portion 35 and the second rib height is less than the microstructure height in the second support rib portion 35.

The intermediate rib 38 is alternatively constructed such that the first intermediate rib 38 a extends from the top edge 28 approximately to a middle of the vertical height of the fill sheet 10 where the first intermediate rib 38 a substantially ends and the second intermediate rib 38 b starts and extends to the bottom edge 30. The ribs 24, 26, 38 are not limited to having these configurations and may be otherwise designed and configured to provide strength and stiffness to the fill sheet 10, such as switching the general configurations of the air intake and outlet ribs 24, 26 and the intermediate ribs 38 or configuring each of the ribs 24, 26, 38 substantially the same.

By alternating the height or positioning of the pairs of first and second ribs 24 a, 24 b, 26 a, 26 b of the inlet side and outlet side ribs 24, 26 and the intermediate ribs 38 so that the localized height of at least one of the pair of first and second ribs 24 a, 24 b, 26 a, 26 b, 38 a, 38 b is preferably greater, specifically at the maximum height H_(x), than the microstructure height H_(s) of the microstructure 11 a for any position along the length of the ribs 24, 26, 38 on the fill sheets 10, 9 a, 9 b, it is ensured that each side of the fill sheet 10, 9 a, 9 b has at least one functioning stiffening member or rib 24, 26, 38 for all vertical positions along the air intake side and the air outlet side 10 a, 10 b, respectively, as well as in the intermediate area or offset 32 between the intake and outlet sides 10 a, 10 b, thereby limiting weak points or sections where the fill sheets 10, 9 a, 9 b may buckle. Additionally, the lower peak height sections of the pairs of first and second ribs 24 a, 24 b, 26 a, 26 b of the intake and outlet side ribs 24, 26, wherein the maximum height H_(x) is present, allow the bands of overlapping microstructure 11 a to stiffen the fill sheet 10, 9 a, 9 b in the air travel direction or generally parallel to the lateral axis 20 by creating minor corrugations which resist bending moment in the plane perpendicular to the applied force at the intake and outlet side ribs 24, 26. This configuration increases the rigidity of the fill sheets 10, 9 a, 9 b for handling and shipping. The configuration of the intake and outlet side ribs 24, 26 and the intermediate rib 38, wherein the full height rib sections or sections with the maximum rib height H_(x) overlap before transitioning to the lower height rib sections or sections with the minimum rib height H_(n) of the first and second ribs 24 a, 24 b, 26 a, 26 b, 38 a, 38 b, respectively, where load is transferred between the pairs of first and second ribs 24 a, 24 b, 26 a, 26 b, 38 a, 38 b of the intake and outlet side ribs 24, 26 and the intermediate ribs 38 strengthens and also adds support at the intake and outlet sides 10 a, 10 b and the intermediate portion of the fill sheets 10, 9 a, 9 b.

In the preferred embodiments, the maximum rib height H_(x) is approximately four hundredths of an inch to three-quarters of an inch (0.04-0.75″) or approximately one hundredth of an inch to one-quarter of an inch (0.01-0.25″) greater than the microstructure height H_(s). The maximum rib height H_(x) of the stiffening members or ribs 24, 26, 38 is not limited to these particular heights and may be otherwise sized and configured based on the expected loading of the stiffening member ribs 24, 26, 38, external loading factors, designer preferences, size of the fill sheet 10, type of cooling medium employed and other design considerations. The maximum height H_(x) of the support ribs 24, 26, 38, however, preferably falls within the preferred range such that the maximum height H_(x) is greater than the microstructure height H_(s) in desired sections or segments while the minimum rib height H_(n) is less than the microstructure height H_(s) and the maximum rib height H_(x). In the preferred embodiments, the minimum rib height H_(n) is approximately zero to one-half inch (0-0.5″) or smaller than the microstructure height H_(s) of the particular fill sheet 10. The minimum rib height H_(n) of the stiffening members or ribs 24, 26, 38 is not limited to these particular heights and may be otherwise sized and configured based on the expected loading of the stiffening member ribs 24, 26, 38, external loading factors, designer preferences, size of the fill sheet 10, type of cooling medium employed and other design considerations. The minimum rib height H_(n) preferably falls within the preferred range such that the minimum rib height is less than the microstructure height H_(s) in desired sections or segments. For example, the minimum rib height H_(n) is about half or less than half of the microstructure height H_(s) and the microstructure height H_(s) is slightly greater than half the maximum rib height H_(x) in the first preferred embodiment (See FIG. 2D). The minimum rib height H_(n) may also be approximately zero, as is shown at the lower portion of the first intermediate rib 38 a and the upper portion of the second intermediate rib 38 b of the first preferred fill sheet 10 (See FIG. 1).

In the first preferred embodiment, the first intermediate rib 38 a includes a top intermediate rib end 39 a and a first intermediate rib end 39 b and the second intermediate rib 38 b includes a second intermediate rib end 39 c and a third intermediate rib end 39 d. The first intermediate rib end 39 b is positioned proximate the second intermediate rib end 39 c on the fill sheets 10, 9 a, 9 b. The first intermediate rib 38 a or the second intermediate rib 38 b is intersected by the lateral axis 20 between the top intermediate rib end 39 a and the third intermediate rib end 39 d, meaning the first intermediate rib 38 a or the second intermediate rib 38 b are intersected by the lateral axis 20 at generally any location along the height of the fill sheets 10, 9 a, 9 b between the top intermediate rib end 39 a and the third intermediate rib end 39 d. In the first preferred embodiment, the lateral axis 20 preferably intersects the first intermediate rib 38 a or the second intermediate rib 38 b at any location between the top edge 28 and the bottom edge 30, as the first intermediate rib 38 a generally extends from the top edge 28 to a central portion of the fill sheet 10, 9 a, 9 b and the second intermediate rib 38 b generally extends from the central portion of the fill sheet 10, 9 a, 9 b, where the second intermediate rib end 39 c is positioned proximate the second intermediate rib end 29 c, to the bottom edge 30. The first and second intermediate ribs 38 a, 38 b are not limited to this preferred configuration and the first and second intermediate ribs 38 a, 38 b may be separated into multiple segments, preferably such that at least one of the segments of the first and second intermediate ribs 38 a, 38 b is intersected by the lateral axis 20 at generally any location along the height of the fill sheets 10, 9 a, 9 b, as is described in further detail below with respect to the intake and outlet side ribs 24, 26.

The first and second inlet and outlet side ribs 24 a, 26 a, 24 b, 26 b of the first preferred embodiment are comprised of a plurality of rib segments 70 a, 70 b, 70 c, 70 d, 80 a, 80 b, 80 c, 80 d, wherein the first inlet side rib 24 a is comprised of a first inlet side rib segment 70 a and a third inlet side rib segment 70 b, the second inlet side rib 24 b is comprised of a second inlet side rib segment 70 c and a fourth inlet side rib segment 70 d, the first outlet side rib 26 a is comprised of a first outlet side rib segment 80 a and a third outlet side rib segment 80 b and the second outlet side rib 26 b is comprised of a second outlet side rib segment 80 c and a fourth outlet side rib segment 80 d. The first inlet side rib segment 70 a includes a top end 71 a and a first end 71 b and the third inlet side rib segment 70 c includes a fourth end 71 e and a fifth end 71 f. The second inlet side rib segment 70 b includes a second end 71 c and a third end 71 d and the fourth inlet side rib segment 70 d includes a sixth end 71 g and a seventh end 70 h. The first outlet side rib segment 80 a includes a top end 81 a and a first end 81 b and the third outlet side rib segment 80 c includes a fourth end 81 e and a fifth end 81 f. The second outlet side rib segment 80 b includes a second end 81 c and a third end 81 d and the fourth outlet side rib segment 80 d includes a sixth end 81 g and a seventh end 80 h. The inlet side rib 24 and outlet side rib 26 are configured such that at least one of the pluralities of segments 70 a, 70 b, 70 c, 70 d, 80 a, 80 b, 80 c, 80 d is intersected by the lateral axis 20 at any position between the top ends 71 a, 81 a and the seventh ends 71 h, 81 h, respectively. In contrast to the first and second intermediate ribs 38 a, 38 b, the rib segments 70 a, 70 b, 70 c, 70 d, 80 a, 80 b, 80 c, 80 d somewhat overlap in the height direction or the water flow direction, such as between the third and fourth ends 71 d, 81 d, 71 e, 81 e and the first and second ends 71 b, 81 b, 71 c, 81 c, for example. The rib segments 70 a, 70 b, 70 c, 70 d, 80 a, 80 b, 80 c, 80 d are not so limited and may be configured without the overlaps in the height direction and may include additional or less segments, although preferably such that at least one of the rib segments 70 a, 70 b, 70 c, 70 d, 80 a, 80 b, 80 c, 80 d of each of the inlet side rib 24 and the outlet side rib 26, respectively, is intersected by the lateral axis 20 at any position between the top and bottom edges 28, 30. The inlet side ribs 24, the outlet side ribs 26 and the intermediate ribs 38, including the respective rib segments 38 a, 38 b, 70 a, 70 b, 70 c, 70 d, 80 a, 80 b, 80 c, 80 d, extend generally parallel to the vertical axis 22 or the intake and outlet sides 10 a, 10 b in the first preferred embodiment, but are not so limited and may be otherwise oriented and configured to provide strength and stiffness to the fill sheets 9 a, 9 b, 10.

In the preferred embodiments, the inlet side rib 24, the outlet side rib 26 and the intermediate rib 38 include the adjacent first and second inlet side ribs 24 a, 24 b, the first and second outlet side ribs 26 a, 26 b and the first and second intermediate ribs 38 a, 38 b, respectively. The pairs of the first and second inlet side ribs 24 a, 24 b, the first and second outlet side ribs 26 a, 26 b and the first and second intermediate ribs 38 a, 38 b are spaced at a lateral spacing SL that is preferably between one-quarter and two inches (¼-2″). The lateral spacing SL is not limited to being between one-quarter and two inches (¼-2″) and may be otherwise sized and configured based on fill sheet 10 loading, external loading factors, designer preferences, size of the fill sheet 10 and other design considerations. The lateral spacing SL of the first and second outlet side ribs 26 a, 26 b is shown in FIG. 2 and the first and second inlet side ribs 24 a, 24 b and the first and second intermediate ribs 38 a, 38 b are also similarly designed and configured to have the lateral spacing SL.

The inlet side rib 24 and the outlet side rib 26, including first and second inlet and outlet side ribs 24 a, 24 b, 26 a, 26 b and have variable heights between the top and bottom edges 28, 30. As a non-limiting example, the outlet side rib 26 and, specifically, the second outlet side rib 26 b includes the second outlet side rib segment 80 b and the fourth outlet side rib segment 80 d with a reduced height portion or portion with the minimum rib height H_(n) of the second outlet side rib 26 b extending between the second outlet side rib segment 80 b and the fourth outlet side rib segment 80 d between the top edge 28 and the bottom edge 30. The second outlet side rib segment 80 b preferably has the rib maximum height H_(x) in the second outlet side rib segment 80 b and the fourth outlet side rib segment 80 d has the rib minimum height H_(n) in a portion between the second and fourth outlet side rib segments 80 b, 80 d. The second outlet side rib 26 b of the preferred embodiment also includes transition portions 110 where the second outlet side rib 26 b transitions between the rib maximum height H_(x) and the rib minimum height H_(n) along the length of the second outlet side rib 26 b. Each of the intake side ribs 24, 24 a, 24 b and the outlet side ribs 26, 26 a, 26 b are preferably similarly configured to the second outlet side rib 26 b, with the rib segments or portions having the rib maximum height H_(x), portions or segments having the rib minimum height H_(n) and the transition portions 110 between the segments with the rib maximum and minimum heights H_(x), H_(n). In addition, the pairs of intake side ribs 24 a, 24 b and outlet side ribs 26 a, 26 b preferably have the transition portions 110 at generally the same lateral positions along the lateral axis 20 and opposing rib maximum and minimum heights H_(x), H_(n) along the lateral axis 20 for the adjacent intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b, respectively. As a non-limiting example, the second outlet side rib segment 80 b preferably has the rib maximum height H_(x) along the lateral axis 20 while the adjacent portion or segment of the first outlet side rib 26 a has the rib minimum height H_(n).

The microstructure 11 a in the heat transfer section 11 of the preferred embodiment has a microstructure height H_(s). The minimum height or first rib height H_(n) is less than the microstructure height H_(s) in a first rib support portion, such as along the intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b wherein the ribs 24 a, 24 b, 26 a, 26 b have the minimum height H_(n). The maximum height H_(x) is, conversely, greater than the microstructure height H_(s) in a second rib support portion, such as along the intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b wherein the ribs 24 a, 24 b, 26 a, 26 b have the maximum height H_(x). The ribs 24 a, 24 b, 26 a, 26 b are not so limited and may have consistently smaller or greater heights than the microstructure height H_(s), depending on design and requirement considerations of the particular fill sheet 10. The ribs 24 a, 24 b, 26 a, 26 b are not limited to the described configuration with the alternating maximum and minimum heights H_(x), H_(n) with the transition portions 110 therebetween and the microstructure height H_(s) being between the maximum and minimum heights H_(x), H_(n) and may be otherwise designed and configured to support the fill sheets 10 based on designer preferences, loads being carried by the fill sheet 10, external factors of the operating environment or other factors that may drive the design and configuration of the intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b. The intermediate rib 38 may be similarly designed and configured as the intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b with the maximum and minimum heights H_(x), H_(n) and the microstructure height H_(s) sized therebetween, but is similarly not so limited, as is described herein. In addition, in the preferred embodiments, the intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b and the intermediate rib 38 has a generally arcuate-shaped cross-section. The intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b and the intermediate rib 38 are not limited to having the arcuate-shaped cross-section and may have alternative cross-sectional shapes, such as solid, squared, triangular or other shapes, as long as the intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b and the intermediate rib 38 are able to perform the preferred functions and withstand the normal operating conditions of the intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b and the intermediate rib 38, as is described herein.

The preferred intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b include the transition portions 110, which has a substantially consistent first taper, therein the intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b transition from the minimum or first rib height H_(n) to the maximum or second rib height H_(x). The transition portions 110 are not limited to having the substantially consistent first taper and may have staged, stepped, sudden or otherwise inconsistent tapers between various heights along their length, but the preferred intake side and outlet side ribs 24 a, 24 b, 26 a, 26 b have the relatively consistent first taper to assist in transitioning loads, for manufacturability, to limit stress concentrations and for additional design considerations.

Referring to FIGS. 7-9, in the second preferred embodiment, the fill sheet 10′ includes the integral drift eliminator 50. The integral drift eliminator 50 of the second preferred embodiment is comprised of an angled tube integral drift eliminator type, with a blocking structure or rib 100 at a drift eliminator inlet 102 where air flow enters the drift eliminator 50 from the heat transfer area 11′ of the fill sheet 10′ in the fill pack 8′. The blocking structure 100 is substantially comprised of a rib or wall in the preferred embodiment. The drift eliminator 50 is not limited to including the blocking rib 100 or to the blocking structure 100 being oriented generally vertically or to being a rib or wall. The blocking structure or rib 100 may be comprised of nearly any structure that provides an impediment or block for cooling fluid flowing directly into the drift eliminator 50 and facilitates drip formation at the inlet 102, preferably on or proximate to the blocking structure 100 so that the cooling fluid drips do not form deep into the drift eliminator 50. The cooling fluid is then able to drain back into the heat transfer area 11′ before exiting the drift eliminator 50 and being lost from the cooling tower.

The blocking structure 100 preferably provides a block to drift, typically comprised of cooled water droplets or cooling fluid, or formation of cooling fluid drips at the inlet 102 so that the cooling fluid does not flow deep into the drift eliminator 50. Formation of drips at the inlet 102 generally prevents the fluid from flowing deep into the drift eliminator 50, potentially escaping into the drift eliminator 50 and out of the heat transfer area 11′. The cooling fluid captured at the inlet 102 of the drift 50 is preferably, ultimately maintained in the heat transfer area 11′ for further disappation of heat and eventually into a catch basin (not shown) below the fill pack 8′ or the individual fill sheets 9 a, 9 b, 10 in the tower (not shown). To prevent the cooled water or cooling fluid film that is flowing through the fill pack 8′ from travelling up and out of the tubes 104 of the drift eliminator 50 and out of the air outlet side 10 b′ of the fill pack 8′, the blocking structure 100 is added at the drift eliminator inlet 102 which acts as a barrier for the water film and a drip formation area to limit flow of the cooling fluid deep into the drift 50. As the water or cooling fluid film reaches the blocking structure 100, the film forms drips which enter the airstream near the drift eliminator inlet 102, rather than farther into the drift eliminator tube 104 toward the air outlet side 10 b. This change in the location of drip formation at the drift eliminator inlet 102 on the blocking structure 100 causes the droplet or drip to be introduced to the air stream in a location earlier in the transition of airflow direction, thereby causing the droplet or drip to impact a bottom tube wall of the drift eliminator tubes 104. The drip from the drift eliminator inlet 102 is thereby removed from the airstream to improve performance and effectiveness of the drift eliminator 50 and the fill pack 8′, because the potentially lost cooled water or other cooling fluid film is blocked at the blocking rib 100 to facilitate drip formation at the inlet 102 to be captured by the drift eliminator tubes 104. The water or cooling fluid, therefore, flows back into the heat transfer area 11′ through a drainage structure 106 for further disappation of heat and eventually into the catch basin below the fill pack 8′ during operation. In the second preferred embodiment, the blocking structure 100 is comprised of a pair of rounded ribs or walls measuring from approximately five hundredths of an inch to two tenths of an inch (0.05″-0.2″) in height and one tenth to one-half inch (0.1″-0.5″) in width. The blocking structure or ribs 100, which are formed at the drift eliminator inlets 102 of each of the fill sheets 10′, 9 a′, 9 b′, align generally adjacent the top walls of each of the drift eliminator inlets 102 of the tubes 104 to act as a barrier for the water film to generally limit the water or other cooling fluid drift from moving into the tubes 104 or facilitate formation of drips to limit flow of the cooling fluid deep into the drift 50.

The second preferred embodiment of the fill sheet 10′ also includes drainage structures 106 (FIG. 8) positioned inwardly toward a center of the sheet 10′ relative to the drift eliminator 50. The drainage structures 106 provide a flowpath for the water or cooling fluid blocked by the blocking structure 100 to flow back into the heat transfer area 11′ for further dissipation of heat. The second preferred fill sheet 10′ is not limited to inclusion of the drainage structure 106 and may include alternatively configured features to direct the captured water or other cooling fluid back into the heat transfer area 11′ or no features without significantly impacting the structure and operation of the second preferred fill sheet 10′.

Referring to FIG. 10, in a third preferred embodiment, a fill sheet 10″ has similar features compared to the first and second preferred fill sheets 10, 10′ and the same reference numerals are utilized to identify similar or the same features, with a double prime symbol (″) utilized to distinguish the features of the third preferred embodiment from the first and second preferred embodiments. The third preferred fill sheet 10″ includes an intermediate rib 38″ including first, second and third intermediate ribs 38 a″, 38 b″, 38 c″. Each of the first, second and third intermediate ribs 38 a″, 38 b″, 38 c″ are laterally spaced from each other and include intermediate rib segments 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 90 g that extend generally vertically or parallel to the vertical axis 22″ to provide strength and stiffness to the third preferred fill sheet 10″.

In the third preferred embodiment, the first intermediate rib 38 a″ includes first and third intermediate rib segments 90 a, 90 c, the second intermediate rib 38 b″ includes second, fourth and fifth intermediate rib segments 90 b, 90 d, 90 e and the third intermediate rib 38 c″ includes sixth and seventh intermediate rib segments 90 f, 90 g. The first intermediate rib segment 90 a includes top and first ends 91 a, 91 b and the second intermediate rib segment 90 b includes second and third ends 91 c, 91 d. The first end 91 a of the first intermediate rib segment 90 a is positioned proximate the second end 91 c of the second intermediate rib segment 90 b such that at least one of the first and second intermediate ribs 90 a, 90 b is intersected by the lateral axis 20″ between the top end 91 a and the third end 91 d, meaning there is generally not an interruption of the first and second intermediate rib segments 90 a, 90 b where the lateral axis 20″ would not intersect either the first or the second intermediate rib segment 90 a, 90 b between the top end 91 a and the third end 91 d. All of the plurality of intermediate rib segments 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 90 g are similarly arranged and configured such that the lateral axis 20″ intersects at least one of the plurality of intermediate rib segments 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 90 g between an end of the intermediate rib segment that is closest to the top edge 28″ of the fill sheet 10″, which is a tenth end 91 k of a sixth intermediate rib segment 90 f in the third preferred embodiment, and an end of the intermediate rib segment that is closest to the bottom edge 30″, which is a fifth end 91 f of a third intermediate rib segment 90 c in the third preferred embodiment. In the third preferred embodiment, the third intermediate rib segment 90 c includes a fourth end 91 e and a fifth end 91 f, the fourth intermediate rib segment 90 d includes a sixth end 91 g and a seventh end 91 h, the fifth intermediate rib segment 90 e includes an eighth end 91 i and a ninth end 91 j, the sixth intermediate rib segment 90 f includes a tenth end 91 k and an eleventh end 91 l and the seventh intermediate rib segment 90 g includes a twelfth end 91 m and a thirteenth end 91 n. To maintain strength and stiffness of the third preferred intermediate rib 38″ the tenth end 91 k is positioned proximate the top end 28″, the eleventh end 91 l is positioned proximate the eighth end 91 i, the ninth end 91 j is positioned proximate the top end 91 a, the first end 91 b is positioned proximate the second end 91 c, the third end 91 d is positioned proximate the twelfth end 91 m, the thirteen end 91 n is positioned proximate the sixth end 91 g, the seventh end 91 h is positioned proximate the fourth end 91 e and the fifth end 91 f is positioned proximate the bottom edge 30″. The third preferred intermediate rib 38″, therefore, extends generally vertically or parallel to the vertical axis 22″ or to the intake and outlet sides 10 a, 10 b such that the lateral axis 20″ intersects at least one of the plurality of intermediate rib segments 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 90 g between the tenth end 91 k and the fifth end 91 f. The sixth intermediate rib segment 90 f and the third intermediate rib segment 90 c are spaced from the top and bottom edges 28″, 30″, but are not so limited and may extend to the top and bottom edges 28″, 30″ or closer to the top and bottom edges 28″, 30″, respectively.

It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed but is intended to cover modifications within the spirit and scope of the present invention as defined by the present disclosure. 

We claim:
 1. A fill sheet for cooling a heat transfer fluid in a cooling tower when assembled into fill packs comprised of pluralities of fill sheets for use in a cross-flow cooling tower, the fill sheet comprising: an air intake end; an air outlet end positioned opposite the air intake end along a lateral axis; a top edge connecting the air intake end and the air outlet end; a bottom edge connecting the air intake end and the air outlet end, the bottom edge positioned opposite the top edge along a vertical axis, the heat transfer fluid configured for flowing between the top edge and the bottom edge; a plurality of flutes extending generally along the lateral axis between the air intake end and the air outlet end; and a transition feature providing a flat section of macrostructure extending generally parallel to the vertical axis, a first flute of the plurality of flutes transitioning from the flat section of the transition feature, the flat section including a rib extending generally parallel to the vertical axis and a spacer proximate to the rib to provide lateral support for the rib.
 2. The fill sheet of claim 1, wherein the transition feature is comprised of an offset that transitions from a flute peak to a flute valley, the offset including the flat section near a center of the offset.
 3. The fill sheet of claim 2, wherein microstructure is integrally formed into the offset.
 4. The fill sheet of claim 2, wherein the offset includes a first offset positioned proximate the air intake end, a third offset positioned proximate the air outlet end and a second offset positioned between the first and third offsets.
 5. The fill sheet of claim 1, wherein the spacer is comprised of a first plurality of spacers positioned proximate the offset.
 6. The fill sheet of claim 1, wherein a heat transfer area is defined between the air intake end, the air outlet end, the bottom edge and the top edge, a microstructure integrally formed on the fill sheet in the heat transfer area, the microstructure has a generally herringbone-shape.
 7. A fill sheet for cooling heat transfer fluid in a cooling tower when assembled into fill packs comprised of pluralities of fill sheets, the fill sheet comprising: an air intake end; an air outlet end positioned opposite the air intake end along a lateral axis; a top edge connecting the air intake end and the air outlet end; a bottom edge connecting the air intake end and the air outlet end, the bottom edge positioned opposite the top edge along a vertical axis; a microstructure formed on the fill sheet; and a support rib extending between the top edge and the bottom edge, the support rib including a first support rib and a second support rib, the first and second support ribs spaced laterally from each other along the lateral axis and extending substantially parallel to the vertical axis, the support rib having a first support rib portion having a first support rib length, the first support rib including a first rib height and the second support rib including a second rib height, the microstructure having a microstructure height, the first rib height being less than the microstructure height in the first support rib portion and the second rib height being greater than the microstructure height in the first support rib portion.
 8. The fill sheet of claim 7, wherein the support rib extends from the top edge to the bottom edge.
 9. The fill sheet of claim 7, wherein the support rib is comprised of an air intake side rib positioned proximate the air intake end and an outlet side rib positioned proximate the air outlet end.
 10. The fill sheet of claim 7, wherein the microstructure is formed into a heat transfer area between the air intake end, the air outlet end, the top edge and the bottom edge, the microstructure has a herringbone arrangement.
 11. The fill sheet of claim 7, wherein the first support rib has a substantially consistent first taper in a transition portion, the first support rib transitioning from the first rib height to the second rib height in the transition portion, the first rib height comprised of a minimum rib height and the second rib height comprised of a maximum rib height.
 12. The fill sheet of claim 7, wherein the support rib has a generally arcuate-shaped cross-section.
 13. A fill sheet for cooling heat transfer fluid in a cooling tower when assembled into fill packs comprised of pluralities of fill sheets, the fill sheet comprising: an air intake end; an air outlet end positioned opposite the air intake end along a lateral axis; a top edge connecting the air intake end and the air outlet end; a bottom edge connecting the air intake end and the air outlet end, the bottom edge positioned opposite the top edge along a vertical axis; and a plurality of ribs positioned generally between the air intake end and the air outlet end, the plurality of ribs including a first rib and a second rib, the first rib extending from a top end to a first end, the second rib including a second end and a third end, the first end positioned proximate the second end, at least one of the first and second ribs being intersected by the lateral axis between the top end and the third end.
 14. The fill sheet of claim 13, wherein the first and second ribs are spaced at a lateral spacing, the lateral spacing being one-quarter to two inches (¼-2″).
 15. The fill sheet of claim 13, further comprising: an offset extending generally parallel to the vertical axis, a first flute of a plurality of flutes transitioning from a first peak at a first side of the offset to a first valley at a second side of the offset, the first and second ribs positioned at the offset.
 16. The fill sheet of claim 15, further comprising: a first plurality of intermediate spacers positioned at the offset.
 17. The fill sheet of claim 16, wherein the first plurality of intermediate spacers includes a first spacer proximate the top edge and a second spacer proximate the bottom edge, the first spacer defining a first spacer axis and the second spacer defining a second spacer axis, the first spacer axis extending to a first side of the vertical axis and the second spacer axis extending to a second opposite side of the vertical axis.
 18. The fill sheet of claim 13, wherein the first end and the second end are spaced at a lateral spacing proximate a middle of the fill sheet.
 19. The fill sheet of claim 13, wherein the first rib includes a first rib segment and a third rib segment, the first rib segment extending from the top edge to the first end and the second rib including a second rib segment, the second rib segment including the second end and the third end.
 20. The fill sheet of claim 19, wherein the top end is positioned proximate the top edge, the third end is positioned proximate the bottom edge and the first and second ends are positioned proximate a middle of the fill sheet.
 21. The fill sheet of claim 13, wherein the first rib includes a first rib segment and a third rib segment, the second rib includes a second rib segment, the first rib segment extending from the top edge to the first end and the second rib segment including the second end and the third end, the second end positioned at the top edge.
 22. The fill sheet of claim 13, wherein the first rib includes a first plurality of rib segments and the second rib includes a second plurality of rib segments, at least one of the first and second plurality of rib segments being intersected by the lateral axis between the top edge and the bottom edge.
 23. The fill sheet of claim 13, wherein the plurality of ribs extends generally parallel to the vertical axis.
 24. The fill sheet of claim 13, wherein the top end is positioned proximate the top edge.
 25. The fill sheet of claim 13, wherein the plurality of ribs includes a third rib, the first, second and third ribs comprise an intermediate rib. 